The U.S. Food and Drug Administration has issued a Refuse to File (RTF) letter in response to Genzyme’s application for approval of alemtuzumab (Lemtrada) as a treatment for MS. The RTF letter requires that Genzyme reorganize the data presented and resubmit its application. Although no new data are required, the RTF is expected to delay any approval of the drug in MS by at least six months. The drug is currently under review by the European Medicines Agency.